Marine mine self protection system

ABSTRACT

This invention discloses a guard to protect a ship against floating mines. The invention comprises a rake-like device held in front of the ship. The device is supported by hydrofoils mounted thereon when the ship is underway at moderate speeds and by float means when the ship is at low speeds or stationary. The mine engaging members depend downwardly into the water in front of the ship from a horizontal support member. The mine engaging members and hydrofoil members pivot to produce minimum drag during turning maneuvers.

United States Patent Bailey 1451 Apr. 11, 1972 [541 MARINE MINE SELF PROTECTION 2,398,753 4/1946 McCarter ..114/240 R SYSTEM Primary Examiner-Trygve M. Blix [72] Inventor Rodd" Bailey Panama Attorney-Richard S. Sciascia, Don D. Doty and William T. [73] Assignee: The United States of America as Sk represented by the Secretary of the Navy 22 Filed: Dec. 3, 1970 [57] ABSTRACT This invention discloses a guard to protect a ship against float- [211 Appl' 94655 ing mines. The invention comprises a rake-like device held in front of the ship. The device is supported by hydrofoils [1.8. CI- R mounted thereon when the i underway at mode -ate [51] Cl 4 "B638 9/00 speeds and by float means when the ship is at low speeds or of Search 1 1 1 I Stationary h i g g g members depend downwardly R C" d into the water in front of the ship from a horizontal support [56] e erences e member. The mine engaging members and hydrofoil members UNITED STATES PATENTS pivot to produce minimum drag during turning maneuvers.

2,3 14,781 3/1943 Ganis ..l14/240 R 10 Claims, 5 Drawing Figures PATENTEDAPR 1 1 1912 3,654,888

sum 1 OF 2 PATENTEDA R 11 I912 3,654,888

SHEET 2 OF 2 STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

FIELD OF THE INVENTION This invention relates to the field of naval architecture as it pertains to marine mine countermeasures. More particularly, the invention relates to a structure that may be applied to existing surface vessels to protect them against floating type marine mines. The nature of the structure permits installation on vessels when they are in theaters of operation where such mines might be encountered and removal therefrom for operation in areas where such mines are not a threat.

Floating type marine mines are a particularhazard to river and harbor surface craft. These mines may be planted from open boats or even from the shore by small groups of people. The mine floats on the surface, or slightly therebelow, and is arranged to detonate upon contact. A variety of firing mechanisms and buoyancy arrangements are readily improvised in the field by espionage personnel engaged in planting the mines. It is, therefore, easy for the mines to be planted by personnel apparently engaged in normal activities such as fishing, for example, or under the cover of darkness and therefore appear in waters previously cleared of such weapons.

Despite their simplicity, these mines pose a serious and constant threat to surface water craft engaged in patrol or supply missions. The mines low visibility, due to the small size and low position in the water, makes avoidance techniques ineffective. Consequently, persons engaging in these normal activities do so at great peril and with considerable apprehension and uncertainty.

DESCRIPTION OF THE PRIOR ART Because of the limited effective range of the mines, a satisfactory solution for individual surface craft is to cause their detonation at a range where they are relatively harmless. This may be satisfactorily accomplished by a structure extending forward of the vessel and extending downwardly into the water. Such a device intercepts the mine at a distance forward of the prow of the vessel which is beyond its effective range. The mine usually detonates upon contact with such structures shattering the tranquility but leaving the protected vessel intact.

An example of this type prior art device is shown in US. Pat. No. 2,3 l4,78l issued to H. J. Gains on Mar. 23, 1943, for a Marine Mine Destroyer. Such devices are useful for the older type of marine mines which were used upon the high seas and were moored in place to be detonated by ship contact. These devices extended far forward of the vessel because of the great charge of explosive material used in these mines.

While satisfactory on the open seas, these prior art devices are, in many ways, unsatisfactory for river and harbor craft. The hydrodynamic drag of the prior devices is great and markedly reduce the perfonnance of the small modestly powered vessels used in riverine service. More important than the power they consume, however, is the adverse effect they have on the steering of the craft on which they are installed and the length of time that their installation and removal requires.

This is particularly true for the case of small high speed motor launches. Such vessels, to be effective in performance of their assigned missions, must come about rapidly. The rudder effect of a large, fixed mine detonator pushed in front of the craft so seriously limits the maneuverability that the vessels have been exposed to the risks of destruction by the floating riverine mine rather than sacrifice their maneuverability.

SUMMARY OF THE INVENTION This invention overcomes the disadvantages of the prior art arrangements by providing an improved fender to protect vessels from floating riverine mines. The device of the invention is characterized as being of low mass, easily attached and removed, of very low drag, self supporting, and effective against the class of mines previously described. These laudatory characteristics are provided by the structure of the device in a manner which will be clearly described herein.

The particular structural details which principally contribute to the effectiveness of the device are self supporting hydrofoils, pivotable mine contactors and detonators, and hinged boom construction. The precise fashion in which these features are embodied in the device and the manner in which they cooperate to provide the improved results are more fully described in connection with the figures illustrating a preferred embodiment of the invention.

An object of the present invention is, therefore, to provide an improved defense against floating marine mines.

Another object of this invention is the provision of a bow mounted fender to intercept and detonate floating mines.

A further object of this invention is a mine intercepting and detonating structure extending forewardly of a surface vessel protected thereby to provide protection from collision with floating objects which are on the course of the vessel.

A further object of the invention is to provide a bow mounted mine fender having low hydrodynamic drag.

Still another object of the invention is the provision of a bow mounted mine fender to be pushed through the water by a vessel to be protected thereby without impeding the maneuverability thereof.

Yet another object of the invention is to provide a fender to intercept marine mines which is supported by hydrodynamic forces generated by propelling the device through the water.

Still another object of the present invention is a bow mounted marine mine fender which has low drag and low resistance to lateral motion such as that generated by the vessel coming about in a small radius.

A further object of the invention is to provide a bow mounted, hydrofoil supported fender for marine mines which permits a ship on which it is installed to maneuver without restriction.

Other objects and many of the attendant advantages will be readily appreciated as the subject invention becomes better understood by reference to the following detailed description, when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates the device of the invention installed on a surface vessel;

FIG. 2 illustrates the mine engaging portion of the invention in partial plan view;

FIG. 3 shows in side elevation one of the mine engaging members;

FIG. 4 is a sectional view of one of the mine engaging members taken along line 4-4 of FIG. 3; and

FIG. 5 is a partial view of the hydrofoil support members with a portion of the connecting float broken away to show mounting details.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 a surface vessel 11 is shown with the device of the invention installed thereon. A bow mounted boom 12 extends forward of vessel 11 to horizontal members 13 hingedly attached thereto. Booms 14 attach to vessel 11 abaft the bow attachment point of boom 12 but still well foreward in the bow regions thereof. Floats 15, at the outboard ends of horizontal members 13, support the device when the vessel is stopped or at very low speed.

It should be noted that, although vessel 11 is illustrated as a cutter type vessel, the invention is applicable to boats and motor launches which are very much smaller. Developmental studies, in fact, have indicated that the invention is perfectly feasible on boats of meters length. Because of the wide variety of water craft to which the device of the invention may be applied, the specific construction of the mounting arrangements for booms 12 and 14 vary considerably. Therefore, no specific mounting arrangement is shown or described, however, conventional mountings such as eye pads and cooperating rings are satisfactory and are readily available from marine stores.

As may be more clearly seen with reference to FIG. 2, horizontal members 13 have mine engaging tines 16 extending downwardly therefrom. Tines 16 may be likened to the tines of a rake that are spaced such that floating mines may not pass therebetween. Horizontal member 13 supports mine engaging tines 16 for engagement with floating surface mines causing the mines to detonate harmlessly ahead of vessel 11 rather than destructively against the hull thereof. Tines 16 are held rigidly with respect to the vertical, but are free to pivot about the vertical axis, as will be more fully disclosed presently.

At the center of horizontal member 13, beneath bow boom 12, central hydrofoil 17 is disposed. Central hydrofoil 17 is configured to support the weight of horizontal member 13 and depending tines 16 at low cruising speeds. If the foreward end of bow boom 12 is free to move in a vertical direction sufficiently to submerge horizontal member 13, a central float 18, shown in broken lines in FIG. 2, may be mounted at the upper end of central hydrofoil 17 to buoy the center of the system when vessel 11 is at rest or at speeds too low for central hydrofoil 17 to provide the necessary lift.

Horizontal members 13 are hingedly joined to the top of center hydrofoil 17 by hinge or universal joints 19, located on either side thereof. Universal joints 19 permit horizontal members 13 to remain just above the surface in a horizontal position despite any roll as vessel 11 comes about.

The outboard ends of horizontal members 13 are supported in a similar manner to the center. Hydrofoil 21 extends downwardly from float mounted at the outboard end of horizontal members 13. Float 15 assures that the outboard ends of horizontal members 13 do not sink below the surface at low speeds or when vessel 11 is at a standstill. Normally, when underway, hydrofoils 21 lift floats 15 clear of the water when the water speed of vessel 11 attains a predetermined speed, i.e., 6 knots or greater.

Booms 12 and 14, as well as horizontal members 13, may be made of any suitable material, such as aluminum tubing, for example. In general, all the structural components of the device of the invention should be constructed of lightweight material, so as to facilitate low speed support by hydrofoil units 17 and 21. Lightweight construction also has obvious advantages with respect to installation, removal, and repair of the system.

Referring to FIGS. 3 and 4, the constructional details of mine engaging tines 16 are more clearly illustrated. A single mine engaging tine 16 is shown as comprising a streamlined body portion 22. Body portion 22 may be made of lightweight metal or plastic and is shaped to ofier a minimum drag as it is pushed through the water. At the foreward end of body portion 22 a vertical mounting rod 23 passes longitudinally therethrough. Bushing 24 encircles rod 23 and provides rotatable bearing support therefore. The bearing action of bushing 24 and rod 23 permits body member 22 to move to a position to minimize the hydrodynamic drag. In this respect, the rotary movement may be likened to a weather vane. An enlarged head 25 at the lower extremity of mounting rod 23 limits downward motion of body portion 22 while cotter pin 26 prevents upward movement thereof.

A striking strip 27 may extend along the leading edge of body portion 22 to engage the mine, if desired. This strip may be made of suitable magnetic material or be a magnet itself. Such a construction assures the conditions for detonation are met for some classes of mines which are triggered either magnetically or by a combination of contact and magnetic influence.

Referring to FIG. 5, the mounting arrangement for hydrofoils 21 is shown. Float 15 is seen to have a support 28 extending therethrough. Thrust bearing 29 is mounted on the lower end of support 28 and has a support shaft 31 rotatably joumaled therein. Shaft 31 supports hydrofoil 21 and is attached thereto by suitable means such as end cap 32. The rotatability of shaft 31 in bearing 29 permits hydrofoil 21 to pivot about the vertical axis and assume a position of minimum drag in the same manner as tines 16.

The foregoing description is sufficiently complete to enable a person versed in the marine engineering arts to make and use the invention. Of course, such a person may incorporate other mechanical details than those shown and described, so long as they are within the scope of good design practice. As an example of such modification within the scope of good design practice, a different means may be used to secure body portion 22 of tine 16 to mounting rod 23 at the upper end than cotter pin 26, which is shown. For example, threaded fasteners may be used for this purpose, if desired. Similarly, some degree of freedom may be exercised in the mounting of body portions 22 on rods 23. That is, the degree of freedom of movement and position of the rod relative to the longitudinal dimension of body portion should be such that the tines move freely to their proper position without either binding or flutter. Such factors differ somewhat from one type vessel to another, but the design factors governing the choice of variables is well within the scope of persons versed in the marine engineering arts.

MODE OF OPERATION The mode of operation of the device is uncomplicated and requires no active participation by members of the vessel on which it is installed. As vessel goes through the water, hydrofoils 17 and 21 generate lift necessary to support members l3 and depending tines 16. This lifting action raises floats l5, and 18, if installed, from the surface of the water, so as to reduce the drag caused thereby. As vessel 11 comes about, body portions 22 pivot about rods 23, so as to afford minimum drag and rudder action. Similarly hydrofoils 17 and 21 pivot in their mountings. Hinges or universal joints 19 permit the members 13 to remain horizontal despite roll occasioned by the turning of vessel 11.

Mines encountered in the water are exploded harmlessly by tines 16. The damage done to tines 16 and members 13 may be easily repaired by replacement of damaged parts.

Obviously, other embodiments and modifications of the subject invention will readily come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing description and the drawings. It is, therefore, to be understood that this invention is not to be limited thereto and that said modifications and embodiments are intended to be included within the scope of the appended claims.

What is claimed is:

l. A defense system to protect a water surface vessel from mines comprising in combination:

bow boom means mounted on the bow of said water surface vessel and extending foreward thereof;

central hydrofoil means mounted on said boom means at the foreward end thereof and extending downwardly therefrom into the water for supporting said boom means when said vessel is moving through said water;

horizontal support means extending outwardly from the end of said boom means generally transverse to the length of said vessel for supporting mine engaging tines therefrom; hinge means attached to said central hydrofoil and to the inboard said horizontal support means so as to join them together for permitting relative hinging motion therebetween;

side boom means attached to the outboard end of said horizontal support means and attached to the foreward respective sides of said surface vessel so as to extend forewardly therefrom for positioning said horizontal support means substantially transverse to the longitudinal dimension of said vessel and at a predetermined distance foreward of the bow thereof;

outboard hydrofoil means mounted on the outboard ends of said horizontal support means for providing dynamic lift therefor when said vessel is underway; and

tine means attached to said horizontal support and extending downwardly therefrom into the water for intercepting mines in the path of said vessel as it is propelled forewardly through the water.

2. A defense system according to claim 1 wherein said central hydrofoil means and said outboard hydrofoil means are rotatably mounted for aligning themselves in accordance with the direction of travel of said vessel to minimize the hydrodynamic drag.

3. A defense system according to claim 1 in which said tine means comprises metallic striking strip for actuating magnetic mines.

4. A defense system according to claim 1 further comprising float means mounted on the upper end of said outboard hydrofoil means for providing buoyancy for said horizontal support means at speeds of said vessel lower than the speed at which said outboard hydrofoil supplies sufficient lift to support said horizontal support means.

5. A defense system according to claim 1 further comprising central float means attached to said central hydrofoil means for buoying said central hydrofoil and horizontal support means at speeds lower than speeds at which said central hydrofoil means develops hydrodynamic lift sufficient to support said horizontal support means.

6. A defense system according to claim 1 in which said tine means further comprise in combination:

rod means attached to the aforesaid horizontal support means and depending therefrom in a substantially vertical fashion so as to constitute an axle for support of said complete tine means;

body means joumaled about said rod means so as to pivot thereabout for minimizing the drag offered by said tine means; and

retaining means attached to said rod means and positioned with respect to said body means for holding said body means in cooperative relation to said rod means.

7. A defense system according to claim 6 further comprising a metallic striking strip mounted on the leading edge of said body means for actuating magnetically triggered mines.

8. A defense system according to claim 7 further including float means attached to the aforesaid outboard hydrofoil means for providing buoyancy therefor at speeds below which said hydrofoil means develop sufiicient lift to be self supportmg.

9. A defense system according to claim 8 in which said outboard hydrofoil means and said float means are attached via rotatable bearing means connected therebetween, so as to permit said hydrofoil to pivot to a position to minimize hydrodynamic drag.

10. A defense system according to claim 9 further comprising central float means mounted for rotatable support of said central hydrofoil means for providing buoying support therefor at speeds below that at which said central hydrofoil becomes self supporting. 

1. A defense system to protect a water surface vessel from mines comprising in combination: bow boom means mounted on the bow of said water surface vessel and extending foreward thereof; central hydrofoiL means mounted on said boom means at the foreward end thereof and extending downwardly therefrom into the water for supporting said boom means when said vessel is moving through said water; horizontal support means extending outwardly from the end of said boom means generally transverse to the length of said vessel for supporting mine engaging tines therefrom; hinge means attached to said central hydrofoil and to the inboard said horizontal support means so as to join them together for permitting relative hinging motion therebetween; side boom means attached to the outboard end of said horizontal support means and attached to the foreward respective sides of said surface vessel so as to extend forewardly therefrom for positioning said horizontal support means substantially transverse to the longitudinal dimension of said vessel and at a predetermined distance foreward of the bow thereof; outboard hydrofoil means mounted on the outboard ends of said horizontal support means for providing dynamic lift therefor when said vessel is underway; and tine means attached to said horizontal support and extending downwardly therefrom into the water for intercepting mines in the path of said vessel as it is propelled forewardly through the water.
 2. A defense system according to claim 1 wherein said central hydrofoil means and said outboard hydrofoil means are rotatably mounted for aligning themselves in accordance with the direction of travel of said vessel to minimize the hydrodynamic drag.
 3. A defense system according to claim 1 in which said tine means comprises metallic striking strip for actuating magnetic mines.
 4. A defense system according to claim 1 further comprising float means mounted on the upper end of said outboard hydrofoil means for providing buoyancy for said horizontal support means at speeds of said vessel lower than the speed at which said outboard hydrofoil supplies sufficient lift to support said horizontal support means.
 5. A defense system according to claim 1 further comprising central float means attached to said central hydrofoil means for buoying said central hydrofoil and horizontal support means at speeds lower than speeds at which said central hydrofoil means develops hydrodynamic lift sufficient to support said horizontal support means.
 6. A defense system according to claim 1 in which said tine means further comprise in combination: rod means attached to the aforesaid horizontal support means and depending therefrom in a substantially vertical fashion so as to constitute an axle for support of said complete tine means; body means journaled about said rod means so as to pivot thereabout for minimizing the drag offered by said tine means; and retaining means attached to said rod means and positioned with respect to said body means for holding said body means in cooperative relation to said rod means.
 7. A defense system according to claim 6 further comprising a metallic striking strip mounted on the leading edge of said body means for actuating magnetically triggered mines.
 8. A defense system according to claim 7 further including float means attached to the aforesaid outboard hydrofoil means for providing buoyancy therefor at speeds below which said hydrofoil means develop sufficient lift to be self supporting.
 9. A defense system according to claim 8 in which said outboard hydrofoil means and said float means are attached via rotatable bearing means connected therebetween, so as to permit said hydrofoil to pivot to a position to minimize hydrodynamic drag.
 10. A defense system according to claim 9 further comprising central float means mounted for rotatable support of said central hydrofoil means for providing buoying support therefor at speeds below that at which said central hydrofoil becomes self supporting. 